Pulverizing mill



May 4 1926.`

C. B. STRACHAN PULVERIZING MILL fill @N+ f, I@

May 4 1926. 1,583,324

a c. B. sTRAcHAN PULVERI Z ING MI LL Filed May 25. 1925 4 2 Sheets-Sheet2 Patented May 4, 1926.

H AUlxrlruo'STA TES PATENT oFrIcEy. @if

VCHARLES BooTHE STRACHAN, 0E lvrascor, TENNESSEE, AssrGNoR ,To STEACHANTUBE MILL COMPANY, A GOREOEATION OF TENNESSEE. 1 Y

.'PULVERIZING- MILL.

Application led May 25, 1925. vSerial No. 32,792.`

of America, and a resident of 'Mascot, in

the county of Knox, State` of Tennessee, have invented new and usefulImprovements 1n Pulverizing Mills, 'which invention is fully set forthin the following specification.l

This invention relates to grinding-or -p'ulf verizing mills of thecharacter ordinarily used for crushing ore, stone or the like, and hasfor its object to provide a mill of such character and constructionvthatk thesame may be operated by a minimum expenditure of power,producing a uniform character of y product and a lminimum amounto-fshines, y

A further object of the invention isjto provide for the. readyseparation (if-the ground product from that which has notbeensufficiently pulverized and without, complicating theapparatus bytheprovision of conveyors, separators and the like.

In the present invention, the ore or stone" being acted upon which hasnot ,been crushed or pulverized kto thedesired condition is separatedfrom the properlyl reduced ,mate rial by centrifugal force, and thisrequires a high speed to bev imparted tothe mill, which speed, in turn,requires that the lparts thereof shall be sucientlymassivenotto havetheir grinding and separating opera: tions interfered with bycentrifugal action which is employed to lseparate the ground from theunground material.- f With these objects in view, the invention consistsof a strong, longitudinallyextending cylindrical shell whose ends areclosed by heads through one of which :the material to be crushed is fedand throughtheother of. which the material finds its vexit-1 'Said headpieces have on thefinterior sides thereof circular chambers whoseinterior. walls are composed of perforated diaphragms lirmly secured tothe head pieces, and "between these diaphragms are'placed a series ofunitary massive cylinders, one within. the other, the diameters ofthecylinders being such as to leave a very material :spacing between theouter vwall'of the interior cylinder and the interior wall of the nextadjacent cylinder, thczinnermost.cylinder being preferably in the formof va solid cylindrical mass. These cylinders vare of uniform length andare retained by the diaphragms of the respective head pieces so as tojust centto the center there `forthe gro-und material.

leave suiiicient play for them to roll freely onejwithin -thevother whenthe mill as a wholeA isl rapidlyrevolved. `The high speed at which .themill isrevolved servestothrow the heavier .,unground particles outwardfrom the center .Y while .the finelyy ground particles remain neartheycenter, and. adja- Preferablyythoughnot necessarily, the

several cylinders have openings or perforations extending therethrough,to the end that the material under vtreatment r will'jpass through saidopenings'. l

y The" inventive ideal .is illustrated in the accompanying, drawings,which drawings are for fthe purposeof illustration'only, and in l vF ig.ll is a kcentral longitudinal section through a mill embodying theinvention; v

. Fig. 2 is a vertical section on the line 2 2 of Fig. 1, looking inthe,y direction of the arrow and Fig. is: avertical section on the line3&3 of Fig. 1, also looking in the directionof the IH-OW,e n

-f K Referring. to the. drawings, in which n like reference rnumeralsindicate likel-parts throughout the lseveral views, 4; isv a strongcylindrical metallshell,- the ends ofV which are closed by an inlet'head 5 andan outlet head- 6, said heads being heldsuiciently againstlthe' ends ofthe `cylinder by rods 7 are formed exitsv passingthrough-openings in thehead and v to leave an open cylindrical chamber 16,

which, in turn,`,is` in free andopencommunication with the channelllvformed in the bearing portion 9. Thefdiaphragm 14:y is secured inposition on the head 5 by means of suitable bolts 17 as willbe readilyunderstood from the drawings.

f .The outlet head Gis provided with acenor `otherwise secured l.a shaft19 taking bears .tral' hub. portion .-18 jwithin which is f keyed ll'Oing in a suitable support or pier 20, and

havingthereon suitable means, as a pulley 21, for connection to a sourceof power.

Surrounding the head piece on the hub 18 is a cylindrical chamber 22from which lead.

diameter ofthe casing 4; The cylinder 28 ispreferably of aunitarypieoefof metal and offjustsuicient length to enable it to fit freelybetween` the diaphragms 14 and 26,A so that theA cylinder28 rests withitslentire weight'on the bottom ofthe interiorof casing 4. In likemanner, a plural-ity of other cylinders 29, 30 and 31, each ofsufficiently less diameterthan' the next exterior one to leave a freespace when itrests upon the interior wall-of the next exterior cylinder.Within the cylinder/31 is-placed a cylinder 32 which, as here shown', isa solid cylindrical mass of metal. All of the cylinders 28 to `82',inclusive, areof uniform length and, asbefore stated, of sufficientlength sothatthey are retained iii-place byt the diaphragme 14and-261while at the same-time being able to roll the millfis revolved onits horizontal longitudinal axis.

In operation, the head pieces and casingarerevolved at la highv rate ofspeed, causing the-cylinder 28 to* roll withinthe casing 4, the cylinder29 Vtoroll withinL cylinder 28,- cylinder` 3()l toroll; within thecylinder 29., cylinder 31 to 'roll ywithin the cylinder 30, and thesolid cylindei32'to-rol1 within the cylinderllsl As each ofthe cylindersis a unitary piece, and vhence of 1 great mass or 1 weight, this -highrateofspeedis maintained without anyv material effect in decreasing thecrushingy actionI between-the adjacent surfaces of the respectivecylinders. The material to be crushed vis fed in throughithe intakehopper f12 in such size=as to readily passfth'rough the openings15`ofithe screen 14,` and by reason of the .unobstructed chamberl,thelarger and heavier particles will enter through-the exteriorperforations 15 while the smaller ones will pass through those nearerthe center. Wheinpieces of material enter intofthe openings between therespective cylinders, they are subjected. to the-.great crushingl weightof thatcylinder plusthe cylinders within it, this ,weight being appliedby the -minimum consumption of power by reason of the fact that eachcylinder rrollson approximately its -own axis, andwithinthe nextadjacent exterior cylinder; There is thus applied avery great dischargeone within the other when' bined'weight ofall of the cylinders-28432,

inclusive. If desired, openingsimay be formed through the several hollowcylinders so as to permit the material to passkthrough said openings andinto the space between thecylinders.

It will 'be observed that they entire mill-is formed of parts of greatstrength and massive weight which permits the-sa1neto -be driven at a.high rateof speed while-atthe same time taking ample advantage oftheweight of the grinding orfcrushi-ng-- elements to efficiently performthis function, and this without the use of any elevators-or otherdevice. This is in marked:- contrastf with previous structures in .whichthe grinding. or. crushmg elements are such that, lffthemachineweredriven at a high rate of speed;

centrifugal action: would reduce the crush'- lng effect of theparts.Moreover, by lreason ofthe fact-that the *centraliy cylinder 32-is solidand thatV alldthe cylinders rollvoneV within therother,vrthelarge'ungroundpartiey cles canV pass through-the millonly by enteringbetween thezcylinders at points above the lowermost of the exitopenings' .and being subjected to the-crushing action `asthe cylindersroll rone withinxthe other..l Furthermore, it will be observedthattheexits from themill arenot -in itsaxis, but onfy the contrary thereareaplurality of exitopeningsbetweeny the axis of the mill and theperiphery of. the chamber 26.. The .result fof this is that centrifugalactionl throws' the larger particles outward in said chamber; therebycrowding the finelyA ground'lpartis cles toward the center wheretheyyfind exitl through lt'he openings 23 in theL head'z.: And forfthesamereasonl the 'largerparti's cles inthe exist chamber'22 are` crowded backthrough the diaphragm and enterfthe open spaces betweenl therolls tobefurther ground.

1. The combination `of a cylindrical .casing, oppositely disposed heads'securedto the respective ends of said casing,linterio'rly projectingannular flangesone on.eachV head piece, a perforateddiaphragm.secured#to each flange whereby a cylindrical chamber isformeel in each head piece', anda 'series of cylinders of .progressivelydecreasing diameters within said casing rolling one within the other andof a length extending from diaphragm to diaphragm.

2. The combination of a cylindrical casing, two oppositely disposed headpieces having radial flanges bolted against lthe opposite ends of saidcasing and annular flanges projecting within said casing, a perforateddiaphragm secured Vto each flange within the casing, and a series ofcylindrical rollers of progressively decreasing diamev ters rolling onewithin the other and extending from one diaphragm to the other.

3. The combination of a head piece havingan outwardly extending hollowhub and an 4inwardly extending annular flange, a bearing for said huband a perforated diaphragm secured to said flange, with an oppositelydisposed head piece having a hub portion and an interiorly extendingannular flange, a perforated diaphragm secured to said last-namedflange, an outwardly projecting shaft connected to said hub, a bearingfor said shaft, a casing extending between said head pieces, and aseries of cylinders of progressively decreasing diameters within saidcasing rolling one within the other and extending from diaphragm todiaphragm. l

4. The combination of a cylindrical casing, a series of cylindricalrollers of uniform length and of progressively decreasing dib5 of saidcasing, a perforated diaphragm forming the interior wall of saidchamber,

and a `series of rollers of progressively decreasing diameters onewithin the other with their end portions abutting said diaphragm andclosing the perforations of said. iaphragm tothe passage of ungroundmaterial through an extended arc below the axis ofsaid casing.

6. The combination of a cylindrical casing, a chambered head piece ateach end of said casing, a perforated diaphragm forming the interiorwall of the two chambers, and a series Vof cylindrical rollers ofprogressively decreasing diameters one within the other rolling withinsaid v casing with their ends abutting* said diaphragms and closing theperforations in said diaphragms against the passage of unground materialthrough an extended arc below the axis of said casing,

In testimony whereof I have signed this specification.

CHARLES BOOTHE STRACHAN.'

